Turning apparatus

ABSTRACT

Turning apparatus comprises a turning tool having a helical cutting edge and a holder therefor to hold the tool fixed with a segment of its helical cutting edge in engagement with the workpiece as the latter is rotated, the tool holder enabling the tool to be rotated a predetermined amount, when the engaged segment of its helical cutting edge has been worn, to advance a fresh segment into engagement with the workpiece.

nited States Patent lLadany [54] TURNING APPARATUS [72] Inventor: ShaulLadany, 71 Rechov Aluf David,

Ramat Gan, Israel [22] Filed: May 15, 1970 [21] Appl. No.: 37,816

[52} US. Cl. .82/1 C, 82/1 R, 29/96 [51] Int. Cl [58] Field ofSearch..82/1, 1 C;29/l02,-103, 105,

[56] References Cited UNITED STATES PATENTS 2,383,958 9/1945 De Vlieg.....408/l33 X Mar. 28, 1972 FOREIGN PATENTS OR APPLICATIONS 607,770 9/1948Great Britain ..29/102 Primary Examiner-Leonidas VlachosAttorney-Benjamin J. Barish [57] ABSTRACT Turning apparatus comprises aturning tool having a helical cutting edge and a holder therefor to holdthe tool fixed with a segment of its helical cutting edge in engagementwith the workpiece as the latter is rotated, the tool holder enablingthe tool to be rotated at predetermined amount, when the engaged segmentof its helical cutting edge has been worn, to advance a fresh segmentinto engagement with the workpiece.

6 Claims, 5 Drawing Figures TURNING APPARATUS BACKGROUND OF THEINVENTION The present invention relates to turning apparatus and tomethods of operating same.

In the known turning apparatus, such as Iathes, the turning tool mustfrequently be sharpened as its cutting edge becomes worn, which is ofcourse costly and time-consuming.

SUMMARY OF THE PRESENT INVENTION According to the present inventionthere is provided turning apparatus comprising a workpiece holder, arotary drive therefor, a turning tool having a helical cutting edge, anda tool holder fixedly holding the turning tool with the longitudinalaxis of the tool at an acute angle to the longitudinal axis of theworkpiece and with a segment of the tool helical cutting edge inengagement with the workpiece as the latter is rotated. The tool holderfurther includes means enabling the tool to be rotated a predeterminedamount, when the engaged segment of its helical edge has been worn, toadvance a fresh segment of its helical cutting edge into engagement withthe workpiece.

It is thus seen that the present invention obviates the need tofrequently resharpen the turning tool since whenever the cutting edgehas been worn, a fresh cutting edge may be advanced to the cuttingposition by merely rotating the tool slightly. When the whole tool hasthus been worn, the complete helical cutting edge may be resharpened, orin some case it may be preferable to merely discard the whole tool.

Further features and advantages of the invention will be apparent fromthe description below.

BRIEF DESCRIPTION OF TI-IE DRAWINGS The invention is herein described,somewhat diagrammatically and by way of example only, with reference tothe accompanying drawings, wherein:

FIG. 1 is a side elevational view of a part of a turning apparatusconstructed in accordance with the present invention;

FIG. 2 is a top plan view of the apparatus of FIG. 1;

FIG. 3 is a partial perspective view of the turning tool used in theapparatus of FIG. 1;

FIG. 4 is a longitudinal sectional view of the turning tool of FIG. 3;and

FIG. 5 is a partial perspective view illustrating a modification of theturning tool of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus illustrated in thedrawings comprises a standard lathe including a headstock 2 and atailstock 4 for holding the workpiece 6, the latter being rotated by adrive 8.

In accordance with the present invention, the turning tool is one havinga helical cutting edge 12 adapted to engage the workpiece 6. The cuttingedge 12 projects from the shank 13 of the tool and may be of rectangularsection with sharp outer edges (FIGS. 3 and 4); alternatively it may beof triangular section, the cutting edge being the apex. The whole tool(i.e. including the shank) may be made of cutting steel, or only thehelical cutting edge, as known per se. It is even contemplated that adrill bit, screw or bolt of conventional construction but having a longpitch may be used as the cutting tool.

The turning tool 10 is held in position by a tool holder 14 which issecured to the bed or other fixed part of the lathe by means of aclamping plate 16. During operation of the turning apparatus, toolholder 14 supports the turning tool 10 so that the longitudinal axis ofthe tool 10 is at an acute angle (A) to the longitudinal axis of theworkpiece 6. The segment of the cutting edge 12 in engagement with theworkpiece is also at an acute angle (a) to the longitudinal axis of theworkpiece, the latter angle depending upon the angle ('y) the helixforms with its own longitudinal axis. For purposes of example, angle Amay be 23, angle y may be 27, and angle a may be 50.

For purposes of adjusting the angle of the cutting tool 10, andparticularly its cutting edge 12, with respect to the work piece,clamping plate 16 may carry a plurality of threaded fasteners 18 adaptedto engage handle 20 of the tool holder 14. Fasteners 18 are released topermit the tool holder to be rotated for adjusting the position of thetool with respect to the workpiece, and then retightened for securelyclamping the tool holder in position.

During operation of the apparatus, only a small segment of the cuttingedge 12 is in engagement with the workpiece as the latter is rotated.When this small segment is worn, it is only necessary to slightly rotatecutting tool 10 for purposes of bringing a fresh segment of the helicalcutting edge 12 into engagement with the workpiece.

For purposes of bringing the fresh segment of the cutting edge intocutting position, cutting tool 10 is provided with a pair of guide parts22 and 24(FIG. 4) each disposed laterally of the helical cutting edgepart 12. Each guide part is formed with one (or two) helical recesses,26 and 28 respectively, corresponding to the helix of the cutting edge12. Tool holder 14 includes a pair of arms 30 and 32 receiving the guideparts 22 and 24 of the cutting tool. Each arm carries a threaded pin 34and 36 adapted to seat within recesses 26 and 28 respectively. When theturning tool 10 is rotated slightly, in order to bring a fresh cuttingsegment of its cutting edge 12 into position, pins 34 and 36 will ridewithin recesses 26 and 28 and will assure that the fresh cutting segmentwill be exactly in the required cutting position with respect to theworkpiece. Tool 10 may be rotated during this operation by hand, or by awrench (not shown) adapted to engage an end of the cutting tool, andafter the fresh segment has been advanced into cutting position,threaded pins 34 and 36 may be threaded down tightly to clamp the toolin this position. Alternatively, there may be provided a separate pairof threaded pins or screws for fixing the tool in position within theholder.

While the guide parts 22 and 24 may be made integrally with the cuttingedge part 12 of the cutting tool, it is preferred that these parts bemade separately and clamped together, as by means of a long bolt 40passing through a bore in all three parts and clamped at one end by anut 42. In this manner, when the cutting edge part 12 of the tool iscompletely worn out, it may be replaced by another cutting part whileretaining the original guiding parts 22 and 24.

FIG. 5 shows a variation, in which the helical cutting edge 12,projecting from the shank 13 of the cutting tool is formed with a radialnotch 50 terminating short of the shank, for dividing the helicalcutting edge into distinct cutting segments.

Many other variations, modifications and applications of the illustratedembodiment will be apparent.

I claim:

1. Turning apparatus comprising a workpiece holder, a rotary drivetherefor, a turning tool having a helical cutting edge, and a toolholder fixedly holding said turning tool with the longitudinal axis ofthe tool at an acute angle to the longitudinal axis of the workpiece andwith a segment of the tool helical cutting edge in engagement with theworkpiece as the latter is rotated, said tool holder including meansenabling the tool to be rotated a predetermined amount, when saidengaged segment of its helical cutting edge has been worn, to advance afresh segment of its helical cutting edge into engagement with theworkpiece.

2. Apparatus as defined in claim 1, wherein said cutting tool includes aguide part cooperable with the tool holder for enabling a new segment ofthe helical cutting edge to be advanced into engagement with theworkpiece.

3. Apparatus as defined in claim 2, wherein said guide part is disposedlaterally of the helical cutting edge and is formed with a helicalrecess corresponding to the helix of said helical cutting edge, saidtool holder including a pin seated in said recess and movable thereinduring the advance of a fresh segment of said helical cutting edge.

4. Apparatus as defined in claim 3, wherein said cutting tool includestwo guide parts, one on each side of said helical cutting edge, and saidtool holder includes a pin seated in the recess of each of said guideparts.

nun-m 5. Apparatus as defined in claim 1, wherein said helical cuttingedge is formed with radial notches dividing same into distinct cuttingsegments.

6. A method of operating turning apparatus comprising a workpieceholder, a rotary drive therefor, a turning tool having a helical cuttingedge, and a tool holder fixedly holding said turning tool with thelongitudinal axis of the tool at an acute angle to the longitudinal axisof the workpiece and with a segment of the tool helical cutting edge inengagement with the workpiece as the latter is rotated, said tool holderincluding means enabling the tool to be rotated a predetermined amount,when said engaged segment ofits helical cutting edge has been worn, toadvance a fresh segment of its helical cutting edge into engagement withthe workpiece, said method comprising, fixedly holding said turning toolwith its longitudinal axis at an acute angle to the longitudinal axis ofthe workpiece and with a segment of its helical cutting edge in cuttingengagement with the workpiece as the workpiece is rotated, and when thesaid engaged segment of the helical cutting edge has been worn, rotatingthe turning tool a predetermined amount to advance a fresh segment ofthe helical cutting edge into engagement with the workpiece.

I i I! i

1. Turning apparatus comprising a workpiece holder, a rotary drivetherefor, a turning tool having a helical cutting edge, and a toolholder fixedly holding said turning tool with the longitudinal axis ofthe tool at an acute angle to the longitudinal axis of the workpiece andwith a segment of the tool helical cutting edge in engagement with theworkpiece as the latter is rotated, said tool holder including meansenabling the tool to be rotated a predetermined amount, when saidengaged segment Of its helical cutting edge has been worn, to advance afresh segment of its helical cutting edge into engagement with theworkpiece.
 2. Apparatus as defined in claim 1, wherein said cutting toolincludes a guide part cooperable with the tool holder for enabling a newsegment of the helical cutting edge to be advanced into engagement withthe workpiece.
 3. Apparatus as defined in claim 2, wherein said guidepart is disposed laterally of the helical cutting edge and is formedwith a helical recess corresponding to the helix of said helical cuttingedge, said tool holder including a pin seated in said recess and movabletherein during the advance of a fresh segment of said helical cuttingedge.
 4. Apparatus as defined in claim 3, wherein said cutting toolincludes two guide parts, one on each side of said helical cutting edge,and said tool holder includes a pin seated in the recess of each of saidguide parts.
 5. Apparatus as defined in claim 1, wherein said helicalcutting edge is formed with radial notches dividing same into distinctcutting segments.
 6. A method of operating turning apparatus comprisinga workpiece holder, a rotary drive therefor, a turning tool having ahelical cutting edge, and a tool holder fixedly holding said turningtool with the longitudinal axis of the tool at an acute angle to thelongitudinal axis of the workpiece and with a segment of the toolhelical cutting edge in engagement with the workpiece as the latter isrotated, said tool holder including means enabling the tool to berotated a predetermined amount, when said engaged segment of its helicalcutting edge has been worn, to advance a fresh segment of its helicalcutting edge into engagement with the workpiece, said method comprising,fixedly holding said turning tool with its longitudinal axis at an acuteangle to the longitudinal axis of the workpiece and with a segment ofits helical cutting edge in cutting engagement with the workpiece as theworkpiece is rotated, and when the said engaged segment of the helicalcutting edge has been worn, rotating the turning tool a predeterminedamount to advance a fresh segment of the helical cutting edge intoengagement with the workpiece.